Add Prepay discount option?

I wanted to use your cat software for my GameHost website.
All features are nice, but how can i add option to the product so if someone wants to prepay (pay for 12 months in advance) to automatically get discount?

For game servers i managed to add per slot prices in Characteristics/Variants, but after they select the number of slots i would like to have for them option to choose for how long will they pay in advance.

Is that achievable (without need to create separate products)?

Thx

Yes, i considered that, but imagine i have let say server with slot options from 10-32 (22 variants with different prices), and if I add another value as renewal period (1, 3, 6, 12 months) with 4 options, can you calculate how many prices i have to add manually (88 to be precise).... tooo much.
It would be easier to have option so based on second Characteristic to reduce price by percent.

Idea:
On the right side to have another module 'Discount options' under product settings.
Discount options:
Name:
Description:
Discount amount - Price modifier (in %, or fixed):

That way I could add:
Name: Renewal period
Desc: 12 months ( 20% Discount)
Disc amount: 960% (which is equal as Price x 12 months - 20%)

This doesn't sound like a bad idea, but how could I change 'quantity' to something else like renewal date, and to add some more information to it?
Or if I could change from number input to dropbox?

Thx, I'll look into that.